A mattress is a large pad for supporting the reclining body, used as a bed or as part of a bed. Mattresses may consist of a quilted or similarly fastened case, usually of heavy cloth, that contains hair, straw, cotton, foam rubber, etc., or a framework of metal springs. Mattresses may also be filled with air or water.
Mattresses are usually placed on top of a bed base which may be solid, as in the case of a platform bed, or elastic, e.g. with an upholstered wood and wire box spring or a slatted foundation. Mattresses may be supplied with a secondary mattress and/or a removable “topper.” A mattress may include an innerspring core and cotton batting or fiberfill. Modern mattresses usually contain either an inner spring core or materials such as latex, viscoelastic or other flexible polyurethane foams. Other fill components include insulator pads over the coils that prevent the bed's upholstery layers from cupping down into the innerspring, as well as polyester fiberfill in the bed's top upholstery layers. In 1899 James Marshall introduced the first individually wrapped pocketed spring coil mattress now commonly known as Marshall coils. Mattresses may also be filled with air or water, or a variety of natural fibers, such as in futons.